CASE REPORT

Interplay between Arrhythmias Originating in the RightVentricular Outflow Tract and the Left Coronary CuspMICHAEL KUHNE, M.D., SVEN KNECHT, PH.D., BEAT SCHAER, M.D.,STEFAN OSSWALD, M.D., and CHRISTIAN STICHERLING, M.D.From the Division of Cardiology, University of Basel Hospital, Basel, Switzerland

A 35-year-old man was referred for ablation of ventricular tachycardia with two different morphologiestriggering each other. After elimination of the first arrhythmia in the right ventricular outflow tract,ablation of the second morphology was performed 8 mm below the left main stem after contrast injectioninto the left coronary cusp through the irrigated-tip ablation catheter. (PACE 2012;00:1–2)

catheter ablation, premature ventricular contraction, right ventricular outflow tract, left coronarycusp

Case PresentationA 35-year-old man was referred for ablation

of premature ventricular contractions (PVCs) andventricular tachycardia (VT) originating from theright ventricular outflow tract (RVOT). The PVCburden on 24-hour Holter monitoring was 28%.Left ventricular ejection fraction was slightlydecreased at 50%. There were no abnormalitieson cardiac magnetic resonance imaging.

There were isolated PVCs with a morphologycompatible with an origin in the RVOT. Interest-ingly, this PVC (#1) repetitively triggered anotherPVC (#2) and frequently runs of VT (Fig. 1A). PVC#2 also had left bundle branch block morphologyand an inferior axis, but an early transition in theprecordial leads. Mapping of PVC #1 showed theearliest activation in the lateral RVOT with a localendocardial activation time of −32 ms (beforeonset of the QRS complex on the surface elec-trocardiogram [ECG]). Radiofrequency (RF) energydelivery (228 seconds, 30 W) at that site eliminatedPVC #1. PVC #2 occurred less frequently and inisolated fashion after ablation of PVC #1. Mappingof PVC #2 showed early activation in the posteriorRVOT (local endocardial activation time −20 ms).Three applications of RF energy at that site had noeffect. The site with the earliest local endocardialactivation time (−37 ms) was found in the leftcoronary cusp (LCC) close to the commissure tothe right coronary cusp. Pace mapping at that site

Conflicts of interest: Michael Kuhne and Christian Sticherlinghave received educational grants from Biosense Webster. SvenKnecht: none declared. Beat Schaer: none declared. StefanOsswald: none declared.

Address for reprints: Michael Kuhne, M.D., Division of Cardi-ology, University Hospital Basel, Petersgraben 4, 4031 Basel,Switzerland. Fax: 41 61 265 45 98; e-mail: kuehnem@uhbs.ch

Received July 7, 2011; revised December 7, 2011; acceptedJanuary 9, 2012.

doi: 10.1111/j.1540-8159.2012.03408.x

showed a perfect (12/12) match (Fig. 1B). Coronaryangiography was performed to localize the ostiumof the left main stem (Fig. 1C). Because of theclose proximity to the left main stem of 8 mm,contrast injection was again performed throughthe irrigated-tip catheter to ensure catheter po-sition in the cusp (Fig. 1D). Power was titratedup from 15 to 25 W and ablation at that site(177 seconds) successfully eliminated the PVCs(Fig. 1E). Twenty-four-hour Holter monitoring3 months after the ablation showed no recurrenceof the PVCs and left ventricular function hadnormalized.

CommentarySeveral ECG characteristics of arrhythmias

originating in the coronary cusps have beenproposed and an early transition in the precordialleads is one of the most consistent ECG features.1,2

In the presented case, a PVC originating fromthe RVOT and a second PVC originating fromthe LCC were present in the same patient. Theassociated PVC burden had led to a decrease inleft ventricular function that normalized 3 monthsafter ablation. Interplay between two ventriculararrhythmias originating in the outflow tract isvery rare. The observation that PVC #1 inducedruns of VT with an LCC origin may suggesttriggered activity as the underlying mechanism,but focal microreentry cannot be ruled out.3Safety is certainly of paramount importance whenperforming RF catheter ablation close to the leftmain stem. The distance between the site whereablation is planned and the orifice of the leftmain stem can be assessed using ultrasoundor coronary angiography. Because of the closeproximity of the site of earliest activation andthe left main stem in our case, we additionallyperformed contrast injection through the irrigated-tip ablation catheter to ensure a position of thecatheter tip in the cusp before starting energydelivery.

C©2012, The Authors. Journal compilation C©2012 Wiley Periodicals, Inc.

PACE, Vol. 00 2012 1

KUHNE, ET AL.

Figure 1. (A) Isolated PVCs with a morphology compatible with an origin in the right ventricularoutflow tract (PVC #1, see asterisk). There was no fusion between normal activation through theHis-Purkinje system and PVC #1. This PVC was repetitively followed by short runs of VT with adifferent morphology. PVC #2 has an inferior axis, a left bundle branch block morphology, andan early transition in the precordial leads. (B) Left: For PVC #2, the site with the earliest localendocardial activation time (−37 ms) was found in the left coronary cusp close to the commissureto the right coronary cusp. Right: Pace mapping at that site showed a perfect match for PVC #2.Ablation at that site effectively eliminated the PVC. (C) Coronary angiography was performedto localize the ostium of the left main stem. (D) Because of the proximity to the left main stemof less than 1 cm, contrast injection was again performed through the irrigated-tip catheter toensure catheter position in the cusp. The arrow denotes the contour of the left coronary cusp.(E) Left posterior oblique view of the two three-dimensional electroanatomic maps obtainedusing CARTO 3 (Biosense Webster, Diamond Bar, CA, USA). Information on local activation ispresented for PVC #2. The bright green tag on the green map shows the site of earliest endocardialactivation (−32 ms) where PVC #1 was ablated in the lateral right ventricular outflow tract (blackarrow). The blue tag on the isochronal activation map of the left ventricular outflow tract and thecoronary cusp shows the site of earliest activation (−37ms) in the left cusp where PVC #2 waseliminated (blue arrow). The site in the posterior right ventricular outflow tract where ablationof PVC #2 was unsuccessful can also be seen (white arrow).

References1. Kanagaratnam L, Tomassoni G, Schweikert R, Pavia S, Bash D,

Beheiry S, Neibauer M, et al. Ventricular tachycardias arising fromthe aortic sinus of valsalva: An under-recognized variant of leftoutflow tract ventricular tachycardia. J Am Coll Cardiol 2001;37:1408–1414.

2. Bala R, Garcia FC, Hutchinson MD, Gerstenfeld EP, Dhruvakumar S,

Dixit S, Cooper JM, et al. Electrocardiographic and electrophysiologicfeatures of ventricular arrhythmias originating from the right/leftcoronary cusp commissure. Heart Rhythm 2010; 7:312–22.

3. Lerman BB, Belardinelli L, West GA, Berne RM, DiMarco JP.Adenosine-sensitive ventricular tachycardia: Evidence suggest-ing cyclic AMP-mediated triggered activity. Circulation 1986;74:270–280.

2 2012 PACE, Vol. 00